The purpose of this study is to evaluate the safety and immunogenicity of a recombinant envelope protein of human immunodeficiency virus-1, gp120 (CHO), combined with an adjuvant, MTP-PE/MF59 in healthy volunteers. It will compare three antigen dose levels, and will also determine the effect of MTP-PE on the cellular and humoral immune response, and this will provide additional information to that currently available regarding the safety of the adjuvant prepartaion.